Derivative spectrophotometry has been shown to have many important applications: for example, studying composition and reaction processes; providing gas signatures; detecting trace chemicals. This technique can become a powerful means for analyzing isomers used in polymer production. In this report, practical examples are given which typify applications of the derivative spectra. Conventional absorption and emission spectra often present overlapping bands not easily resolved by conventional means; band resolution usually is facilitated by first-and second-derivative spectra obtained from spectrophotometric measurements. Numerical methods based on both off-line and on-line computer processing are presented for generating first-and second-derivative spectra, and these techniques are discussed fully. With these methods, the contribution of background noise is emphasized. Ways to reduce this noise are given.
F. Grum, D. Paine, and L. Zoeller, "Derivative Absorption and Emission Spectrophotometry," Appl. Opt. 11, 93-98 (1972)